A structure to vary an outer shape of a mobile unit has been researched, aiming to alter aerodynamic characteristics of mobile units such as vehicles or an aircraft. For example, JP2004-516188 below (hereinafter referred to as Patent Document 1) describes a surface shape variable device which is configured to form an outer panel of a vehicle with a flexible material, and vary a shape of the outer panel by a mechanical position-adjusting device disposed inside the vehicle for the outer panel.